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<html>
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        <title></title>
        <style type="text/css">
           #father1 div{color: red;}
           #father2 span{color: blue;}
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    <body>
        <div id="father1">
            <div>绿叶学习网</div>
            <div>绿叶学习网</div>
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        <div id="father2">
            <p>绿叶学习网</p>
            <p>绿叶学习网</p>
            <span>绿叶学习网</span>
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